1. Field of the Invention
The present invention relates to a gaseous fuel storage and transfer system for use in an automotive vehicle.
2. Disclosure Information
Gaseous fuel storage and supply systems for automotive vehicles present unique challenges to automotive designers, inasmuch as such fuel systems require the handling of gases under relatively high pressures, as opposed to the modest pressures associated with the handling of liquid fuels such as gasoline and Diesel fuel. Furthermore, certain compressed gases such as hydrogen and natural gas present the additional challenge that such gases are buoyant, as opposed to the lack of buoyancy generally present with vapors generated by liquid hydrocarbon fuels. In addition, hydrogen is not only buoyant, but also odorless and has a smaller molecular size, as compared with vapors generated by liquid hydrocarbon fuels. All of these characteristics render compressed fuel gases more difficult to store.
The need to store compressed gases under relatively high pressure and automotive safety requirements impose an added round of complexity in the design process associated with automotive vehicles because fuel tanks for such gases must have much greater strength than liquid storage tanks, to accommodate much higher pressures. Moreover, the useful life of such pressure vessels must be monitored to assure that an adequate margin of safety is maintained, while at the same time allowing onboard tanks to be filled to their maximum safe and practicable (operation limit) capacity, to meet vehicle range design expectations.
Compressed gas storage tank monitoring systems generally use valving arrangements which are usually grossly biased towards underfilling, with the result that the energy density available with such tank systems has generally not been satisfactory, with the obvious negative impact upon vehicle range.
The system and method according to present invention allows maximum practicable filling of compressed gas tanks, while monitoring the useful life of the tank so as to allow tank integrity to be maintained in an efficient manner.